Device for manufacturing twist-drills



H. A. WILLIAMS. Device for Manufacturing Twist Drills.

No. 234,362. Patented Nov. 9, 1880.

UNrTnn STATES PATENT @rrrea.

HENRY A. WILLIAMS, OF TAUNTON, MASSACHUSETTS.

DEVICE FOR MANUFACTURING TWiST-DRILLS.

SPECIFICATION forming part of Letters Patent No. 234,362, dated November9, 1880.

Application filed September 30, 1879.

To all whom it may concern:

Be it known that I, HENRY A. WILLIAMS, a resident of Taunton, Bristolcounty,Massachusetts, have invented new and useful Improvements inDevices for the Manufacture of Twist-Drills, of which the following is aspecification.

My invention relates to the manufacture of twist-drills by forming thegrooves with rollerdies and producing the spiral form by the twistingprocess.

Such drills have been produced by these methods, and although not assatisfactory as is desirable, yet possessing qualities so superior tothose made by the ordinary milling process that it is highly desirableto attain the greatest possible perfection in the devices for so makingthem.

To this end my invention consists of improvements in the roller-dies forproducing the grooves in the drills, and also in the clamping-diesemployed to produce the twist of the same.

In the accompanying drawings, Figure 1 represents the blank a, fromwhich a drill is to be made. In Fig. 2, brepresents the same after thegrooves 0 have been rolled in it. Fig. 3 is the same after being twistedand ground to the size required and trued. Fig. 4 represents the samething when completed. Fig. 5 is a side elevation of a pair of rolls forforming the grooves in the blanks, showing the shape of the die-grooveswhich I make for producing the said grooves of the blank. Fig. 6 is aside elevation of dies to be used for holding the blank after it hasbeen grooved to be drawn by the twisting devices. transverse section ofFig. 6 on line a w.

e f 9 represent three flatteninggrooves or roller-dies, such as I makefor the first operation. They are essentially round, except the bottomof each half, which is flat. The diameter of the round portions is thesame in each, but the flat is increased in each a little successively.These grooves flatten the blanks on opposite sides preparatory togrooving them, and in doing so widen it the other way, in whichdirection the metal is preferably allowed to be displaced in theseoperations rather than lengthwise.

h is a round die-groove next in succession,

Fig. 7 is a' in which the flattened blank is turned up edgewise andcompressed a little on its round sides.

41, and 7c are die-grooves which are circular onthe sides the same asthe others, but ribbed or tongue-shaped on the bottoms, suitably forgrooving the flat sides of the blank. The ribs or tongues of thesegrooves are progressively increased in development of the form anddimensions for progressively producing the com plete grooves in theblank, and after passing the blank through the groove h, as abovestated, itis passed through t, then back through h, next through j, backagain through It, then through 70, and finally through hthat is, afterpassing through each of the tongue-grooves it is passed through h beforegoing through the next tongue-groove.

By this combination of roller-dies it is believed that drills of muchbetter quality in respect of the density, toughness, and homogeneity ofthe metal may be produced than by any other contrivance yet made. Theoperation is so perfect that I roll small sizes up to a quarter-inch indiameter cold, and the drills so made are found in practice to be muchtougher and more durable than when rolled hot.

I believe also that up to half-inch and even larger they may becold-rolled with equal advantage by these dies. If desired a greaternumber of tongued die-grooves may, of course, be employed to develop thegrooves in the blanks more gradually, and-I do not limit myself to thenumber shown.

After thus grooving the blanks I use the clamping-dies m and clamps nfor holding them for twisting by drawing therefrom with a rotatingtwister, which clamps and dies differ from those used in auger-twistingin that the dies are ribbed or tongued to correspond with and fit in thegrooves of the blanks, and are of equal or greater len gth than thegrooved portion of the blanks, and thereby prevent the crookin g andbending of the blanks, that would occur on the side opposite to or backof the side out of which they are drawn if said dies were of less, ormaterially less, length than the portion of the blank to be twisted. Thetendency of a twist-drill blank to crook in this manner is much greaterthan the flat augerblank, be-

cause the body of metal is so much greater in l 2. The combination ofthe clamps n and 10 proportion to the breadth. Hence the short straightdie-bars m, fitting into the straight dies, such as serve for theangers, will not angroot'es of the drill-blanks and extending the saferfor these drills. whole length thereof as set forth.

I claim as my improvement in devices for manufacturing twist'drillsHENRY VILLIAMS' 1. The series ot'roller-die grooves ofg, round-\Vitnesses: ing or gaging die-groove h, and the series of F. A. THAYER,p grooves ij k, jointly, as herein shown. W. J. MORGAN.

